class_docstr: An object detector model which can be trained using Model Maker's training API.
  
  Attributes:
    loss_trackers: List of tf.keras.metrics.Mean objects used to track the loss
      during training.
code: def _get_model_config(
      self,
      generator_config: configs.retinanet.DetectionGenerator = configs.retinanet.DetectionGenerator(),
  ) -> configs.retinanet.RetinaNet:
      model_config = configs.retinanet.RetinaNet(
          min_level=self._model_spec.min_level,
          max_level=self._model_spec.max_level,
          num_classes=self._num_classes,
          input_size=self._model_spec.input_image_shape,
          anchor=configs.retinanet.Anchor(
              num_scales=3, aspect_ratios=[0.5, 1.0, 2.0], anchor_size=3
          ),
          backbone=configs.backbones.Backbone(
              type="mobilenet",
              mobilenet=configs.backbones.MobileNet(
                  model_id=self._model_spec.model_id
              ),
          ),
          decoder=configs.decoders.Decoder(
              type="fpn",
              fpn=configs.decoders.FPN(
                  num_filters=128,
                  use_separable_conv=True,
                  use_keras_layer=True,
              ),
          ),
          head=configs.retinanet.RetinaNetHead(
              num_filters=128, use_separable_conv=True
          ),
          detection_generator=generator_config,
          norm_activation=configs.common.NormActivation(
              activation="relu6"
          ),
      )
      return model_config
  
imports: import os
  from typing import Mapping, Optional, Sequence, Union
  import tensorflow
  from mediapipe.model_maker.python.vision.object_detector import detection
  from mediapipe.model_maker.python.vision.object_detector import model_options
  from mediapipe.model_maker.python.vision.object_detector import model_spec
  from official.core import config_definitions
  from official.projects.qat.vision.configs import common
  from official.projects.qat.vision.modeling import factory
  from official.vision import configs
  from official.vision.losses import focal_loss
  from official.vision.losses import loss_utils
  from official.vision.modeling import factory
  from official.vision.modeling import retinanet_model
  from official.vision.modeling.layers import detection_generator
label_desc: Use image node_id 2 for calling the ObjectDetectorModel obj's underlying member method code with example usage: obj._get_model_config(generator_config) and returns: model_config